The present disclosure relates to procatalyst compositions having a multiple internal electron donor which includes silyl ester and the incorporation of the same in catalyst compositions and the process of making olefin-based polymers using said catalyst compositions.
Worldwide demand for olefin-based polymers continues to grow as applications for these polymers become more diverse and more sophisticated. Known are Ziegler-Natta catalyst compositions for the production of olefin-based polymers. Ziegler-Natta catalyst compositions typically include a procatalyst containing a transition metal halide (i.e., titanium, chromium, vanadium), a cocatalyst such as an organoaluminum compound, and optionally an external electron donor and/or an activity limiting agent. Ziegler-Natta catalyzed olefin-based polymers typically exhibit a narrow range of molecular weight distribution and low flexural modulus. Given the perennial emergence of new applications for olefin-based polymers, the art recognizes the need for olefin-based polymers with improved and varied properties. Desirable would be Ziegler-Natta catalyst compositions for the production olefin-based polymers that exhibit high hydrogen response during polymerization and produce propylene-based polymers with broad molecular weight distribution.